Launcher

A launcher (alternatively called a frontend or launcher frontend, a GUI launcher, or also a Doom launcher, not to be confused with the software of the same name) is a program, typically with a GUI, that allows the user to start Doom by using a graphical interface as opposed to the command line. Most of the common commands used for setting up the game can be accessed by a launcher, such as the skill level and the map to start on. Various launchers for Doom-engine games exist. Some are included as part of precompiled source ports, while others must be installed separately. Most notably, Doom95 has a GUI launcher (which can be deactivated with the command line argument). More recent, popular launchers include ZDL and Doom Launcher.

History
When Doom 1.1 was first released on December 16, 1993, it came with a  command parameter, allowing users to load external PWADs in order to be able to play any kind of mod content. This was the only direct way of loading PWADs into the game, as the in-game menus were otherwise dedicated purely to the three official episodes and various options to tweak the game's look and performance, although a frontend for multiplayer, DeathManager!, shipped with Doom, Heretic and Hexen. For more complex mods such as total conversions, it was necessary to merge the PWADs into the IWAD itself, as allowed by programs such as DeuTex and New WAD Tool.

Because of this, in the early days of Doom modding, launcher options were notably limited. id Software eventually published two, the first as part of Doom on Macintosh on June 27, 1995, and the second as part of Doom95 on August 20, 1996. As both the Apple Macintosh and Microsoft Windows computers featured a graphical interface, unlike the DOS operating system, a launcher was deemed useful and appropriate for these new desktop environments. These two launchers were fairly comprehensive for the time, allowing users to start the game using a variety of pre-set options, launch and load PWADs, and more easily set up multiplayer games. The Doom95 launcher is automatically activated when launching the program, though it can be deactivated with the command line argument. For MacDoom, the frontend is instead displayed when pressing S on the menu after launching the game.

Starting from the mid 90's, a different type of launcher began to emerge, in the form of frontends specifically dedicated to select compilations of PWADs. The most well known of these was DOOM-IT, a program by Chris Badger for the Master Levels for Doom II and Maximum Doom, allowing the user to browse and play the various .WAD files present on both discs, as well as read relevant information for them. Other CDs released commercially during this time, such as D!Zone, also offered their own frontends like Doom/Master, which proved crucial in browsing the hundreds, sometimes thousands of .WAD files present on such discs. Other multiplayer frontends continued to be made as well, such as the one present in DWANGO which also shipped in some copies of Doom.

Following the Doom source code release on December 23, 1997 and the emergence of source ports and port-specific PWADs, the increased complexities gradually led the necessity of brand new launchers to support the new features and options now available. Certain source ports in the early 2000s, such as Doom Legacy, Doomsday and Risen3D started to be bundled with their own launcher frontends, while other ports, such as ZDoom or ZDaemon, had third-party launchers specifically created to cater to their specific features but that sometimes have to be installed separately, with ZDL being a notable and popular example. Multiplayer browsers primarily aimed at server hosting, such as Doomseeker and Doom Explorer also offer robust launchers for single player options.

More recent years have seen the emergence of more complex, all-purpose launchers meant to support a wide range of source ports and options, and contain features such as playlists, tagging, statistics and more. Recent examples include the new ZDL forks, Doom Launcher, Rocket Launcher, Arachnotron and others.

Standalone launchers

 * Doom/Master
 * The King Doom Experience (KDX)
 * ZDL
 * Doom Launcher
 * Rocket Launcher
 * ZDoom Executor
 * Doomie
 * Arachnotron
 * Doom Runner
 * AceCorp Launcher

Bundled with source ports

 * Doom on Macintosh
 * Doom95
 * Doom Legacy
 * Doomsday
 * Risen3D
 * Eternity Engine
 * DSDA-Doom (currently separate, with planned integration in the future)
 * PsyDoom

Bundled with server browsers

 * Doomseeker
 * Doom Explorer